Power transmission system



Jam.v 19, 1943. A. c. DURDIN, JR

POWER TRANSMISS ION SYSTEM Filed July 8, 193s 2 Sheds-Sheet' l ATTORNEYS.

I Jan. 19, 1943.

A. c. DURIN, JR 2,308,868 POWER TRANSMISSIN SYSTE Filed July a. .1938 g sheets-Sheet 2 INVENTOR.

Patented Jan. 19, 1943 UNITED STATES PATENT OFFICE 20 Claims.

The present invention relates to power transmission systems and has for its general object the provision of a system in which a driven member is maintained at a substantially constant speed irrespective oi variations in speed of a driving member.

While the present invention is directed generally to systems in which power is transmitted from a variable speed driving member to a member to be driven at a constant speed, it is more specifically directed to systems in which a variable speed railway car wheel axle or vehicle motor is connected to a constant speed compressor utiliZed in air conditioning the railway car or motor vehicle. Consequently, the specific embodiments of the invention to be described hereinafter have been illustrated in connection with this type of equipment. When a constant speed compressor Unit is driven from a wheel axle, the aXle is ordinarily provided with a driving pulley adapted to drive the compressor through a driven pulley. The pulleys are interconnected through a variable speed-ratio transmission, usually either of the friction or electromagnetic type. These transmissions have the disadvantage thatl at higher speeds, say, when the train is moving at 90 miles per hour, the power required to drive the compressor at its normal speed is approximately twice as great as the power required to drive it at the same speed when the train is moving at 45 miles an hour, which speed may be consideredforthe purpose of illustration-as the normal speed and the speed at which the maximum eiiciency of transmission is obtainable. The increased power required to drive the compressor at the higher train speed results from the fact that the torque necessary to drive the compressor is then obtained from a shaft rotating at twice the speed at which maximum eniciency is obtainable. This disadvantage may be overcome by using a power transmission in which the ratio of the diameters of the driving and driven members is varied to avoid slippage between the shafts.

The present invention is directed to a new and improved power transmission system of this type. In its preferred form it comprises a pair of pulleys, one of which is of the variable diameter type, interconnected by a belt or the like and a centriiugally controlled fluid pressure generating means adapted to regulate the effective diameter of the variable diameter pulley.

The primary object of the present invention is to provide a new and improved uid pressure actuated, centrifugally controlled power trans-.

mission system.

A further object of the invent-ion is to provide a power transmission system with a new and improved centrifugally controlled means for regulating the speed ratio of interconnected driving and driven members.

A further object of the invention is to provide a power transmission system of the type described with a speed regulating means comprising iuid pressure generating means, a power transmission member controlled thereby, and valve means centrifugally controlled in response to the speed of a driven member of the system for controlling the effect of the iluid pressure means on the cong varying the eiective diameter of the Variable diameter pulley by varyingy the force applied to the belt.

A further object of the invention is a power transmission system in which the speed ratio of the driving and driven members is controlled by a unit which may be constructed separate from the power system and installed in newor existing systems with a minimum of effort and expense.

A further object of the invention is to provide a power transmission system in which the speed ratio of the driving and driven members is controlled by means of the type referred to above that is adapted to vary the position of one of said members with respect to the other.

A still further object of the invention is to provide a power transmission system comprising a pair of variable diameter pulleys, the diameter of one of which is varied by fluid pressure actuated centrifugally controlled means and that of the other by the tension o the belt.

Other objects and advantages of the apparatus will become more apparent from the ensuing description in the course or" which reference is had to the accompanying drawings, in which:

Fig. 1 is a top plan view of a preferred form of the present invention illustrated in conjunction with the drive of a constant speed compressor unit from a variable speed driven shaft;

Fig. 2 is a side elevation view of the apparatus shown in Fig. l;

Fig. 3 is an enlarged longitudinal elevation view, partly in section, of the speed-ratio regulating unit of the present invention;

Fig. 4 is an end elevation of the unit shown in Fig. 3;

Fig. 5 is a perspective View of the base plate of the unit illustrated in the previous figures, illustrating in detail the positions of the various .oil ducts;

Fig. 6 is a side elevation, pantly in section, of a modified form of the present invention;

Fig. 7 is a diagrammatic side elevation view of a further modification of the invention with parts thereof omitted for the sake of clarity; and

Fig. 8 `is a fragmentary longitudinal vertical sectional view through the driving shaft and speed-ratio varying means of the system illustrated in Fig. 7.

Fig. 9 is a fragmentary view showing in detail the valve and governor -control mechanism of the embodiment shown in Fig. 6.

Referring now more specifically to Figs. 1 to 5, inclusive, of the drawings, reference numeral ID indicates a variable speed driving shaft such as a railway car wheel `axle or the power take-off shaft of a motor truck transmission. The speed of rotation of this shaft is variable because of the variation in the rate of travel of the car or truck. A driving pulley I I of the variable diameter type comprising two pulley halves I2 is mounted for rotation with the shaft I0. The pulley halves are each provided with hubs i3 slidable on the shaft but splined to the latter so as to transmit power applied to shaft I0. The pulley halves are resiliently biased toward each other (i. e., to the maximum diameter position) by a pair of compression springs I4 abutting at their inner ends against the hubs I3 and at their outer ends against collars I5 adjustably secured in suitable manner to the shaft I 0.

The transmission of power from the drive shaft I is accomplished preferably, but not necessarily, through .a standard V-belt interconnecting the driving pulley II to a constant diameter driven pulley I'I. The driven pulley is fixedly attached to a driven shaft I8 which is j'ournraled for rotation in a pair of spaced apart bearing housings I9 supported upon bearing brackets 20 (see Fig. 2). The driven shaft is coupled by a coupling 2|, of any standard type, to a compressor unit 22 of the constant speed type ordinarily Used in mechanical refrigeration. For purpose of illustrati-on, the compressor intake has been illustrated by reference numeral 23 and the outlet by reference numeral 24.

The variable speed-ratio means of the present invention also comprises an idler pulley 25 rotatably mounted upon a relatively short shaft 26 mounted directly underneath the upper segment of the V-belt I6, as clearly illustrated in Fig. 2. The pulley bears against the under side of the belt with a force determined by control means described herein-after. An `advantage resulting from locating the pulley beneath the upper segment rof the belt is that the belt fibres Iare always pulley 25, and, consequently the pres-sure applied to ithe belt, is controlled by means of a vertically disposed piston rod 29 extending into the connes of a cylinder 30. The upper end of the cylinder is adapted to be closed by an apcrtured cylinder head 3| removably secured to the cylinder by means of a plurality of cap screws 32. The lower end of the piston has attached thereto a piston rod 33, a leather sealing cup 34 'and a follower 35. These are all secured to the piston rod by means of 'a retaining nut 36.

The piston and bed plate are guided in their movements by la pair of guides 31 formed integrally with and at opposite sides of the cylinder. The guides are apertured to receive a pair of guide rods 38 secured to the lower side of the bed plate 28 by retaining nuts 38.

The power necessary to generate the fluid pressure required adjustably to position the bed plate and the idler pulley is derived from the drive shaft and belt through a spur gear 40 mounted on shaft 28 adjacent the idler pulley. Gear 40 meshes with a driving pinion 4I mounted at the end of a gear pump shaft 42. The gear pump is enclosed within ay suitable housing 43 provided with a removable end wall 44 through which access may be had to the co-operatively associated gear pump members 45 and 46 which `are adapted, when rotated, to furnish the fluid pressure neces-sary for proper operation of .the system. While a pump of the type to be described is a preferred source of power it should be understood that in its broader aspects the present invention may be utilized with other sources of power. For instance, the source of power might very well be a pressure tank and an associated independently driven compressor, or the like.

The inlet port of .the gear pump is connected by a conduit 41 to an oil reservoir 48 which is, like the gear pump, supported upon the base plate 28. The reservoir m-ay be filled with any suitable uid such as oil or water or, if desired, a

gaseous medium may be used as the actuating fluid.

The reservoir may be filled with the fluid which, for the purpose of illustration, is -assumed to be oil, through an opening 49 adapted to be closed with a cap 58 provided with a breather opening 5I The outlet port of the gear pump is connected by a duct 52 to a horizontally disposed duct 53 formed in the bed plate. The latter duct may be conveniently formed by a drilling operation and the open end of the duct may be closed by a suitable plug. Excess oil is returned to the reservoir through a vertically disposed branch or by-pass duct 54 extending upwardly from the duct 53 to the bottom of the oil reservoir. The pressure generated by the gear pump is applied to the underside of the piston through a vertical duct 55 extending from the duct 53 to the underside of the piston through the piston rod 29.

The pressure to which the piston is subjected is controlled in a manner more specifically described hereinafter by centrifugal means rotating at a speed proportional to the speed of the driven member so as to maintain the speed of the latter substantially constant, irrespective of variations in speed of the driving member. This pressure control is effected through a control of the amount of oil permitted to flow from the outlet side of the oil pump to the reservoir through the duct 53 and the by-pass duct 54. The amount of oil by-passed from the outlet of the pump to the reservoiris .governed by a valve 55 slidablymounted in a valvechamb'ervSl. Thelleakage of oil along the valve stem 58 is prevented by a suitable stufling box 59.

In-order to provide an arrangement whereby the driving pulley is maintained at its maximum diameter while the apparatus is at rest and the diameter is gradually decreasedas the speed of the driving shaft increases above -a .predetermined value at which the driven member rotates at its normal speed, the bypass valve is biased to its open position by a spring 60 bearing against the side of the bed plate and an actuating lever 6l mounted upon a rock -shaft 62.

The rock shaft is rotatably 'mounted upon a bear- A ing block 63 supported by Lone of the bearing brackets 21.

The position of the valve is controlled by centrifugal ,means acting upon the rock shaft 62 through a yoke 64 .co-operatively 'associated A'at its'fupper rend with 'a collar 65 movable longitudinally .of the shaft 2'6. The shaft 26is provided with'arlxedly mounted collar 65 upon which are mounted the diametrically opposed "governor varms and balls 6l pivotally connected directly to th'exed collar and by means of linkage members 68 vto the slidable collar. y

In order that the movable mechanism of the speed-ratio controlling means described `-above may perform its function without interfering with the movement of the belt, the belt length may be increased somewhat as indicated in Fig. 2 so that the major portion of 'the controlling means vlies between the upper and lower segments of the belt. The control means, which is seen to comprise an integral unit, is best supported at one side of the belt by a bracket 69. yThe bracket may be secured to suitable 'supporting structure either independent of the structure supporting the compressor or upon the same base 69', as illustrated clearly in Fig. 2.

In the description of the operation,i`t is assumed first that the 'driving shaft and, therefore, the remainder of the mechanism thus far described are at rest. At this time the governor balls 61 lie nearest the axis of the shaft V2li and consequently the valve controlling the passage of iiuid vfrom the gear pump directly to the fluid reservoir is open. yThe piston 33 is at its lowermost position and the pressure applied to the belt a minimum. Consequently, the two halves l2 -of the variable diameter driving pulley are nearest each other. When the driving shaft I -is -rotated, the driving pulley rotates and it drivesv the driven pulley Il through 4the belt. 'I'he belt rotates the idler pulley and its supporting shaft and consequently the pump is operated. However, since the bypass conduit is Aopen, Ivas a result of the valve 56 being biased to its openposition, no pressure is applied bythe idler pulley to the belt. Consequently, the drive of the driven shaft is initiated at the highest speed ratio because the driving pulley is at its maximum effective diameter position. When the 'speed of the driven shaft, and likewise the peripheral speedl of the belt, which is proportional to the speed of the driven shaft, reaches its normal operating speed the centrifugal force of the governor balls overcomes the bias of the valve spring, thereby partially closing the valve. of the valve results inthe application of pressure to the un'der side of piston 33, wherebythe piston is raised and pressure applied to the belt. The belt is moved upwardly Iand the halves I2 of the driving pulley forced apart against the force of The partial closure the biasing y springs to decrease L`the effective -di- Aameter ofthe belt. As the speedy ofthe driving shaft increases, the Valve isgradually closed to creases, the valve is returned toward its open position by the spring. The pressure applied to the belt is reduced andthe effective diameter ofthe driving pulley increased, vagain to maintain the speed of the driven member substantially constant.

It may be W'ell'to mention at this pointthat when "the driving member is rotating below a speed at which the centrifugal force of the governor balls is insui'cient to overcomethe'bias of the valve spring, the driven member is rotated at a speed proportional to the speed ofthe driving member. However, when the speed of the driven 'member reaches its normal operating speed, the centrifugal force overcomes the bias and `effects gradual closure of the valve as vthe speed of the driving members increases, v`as fully explained above. When the speed of the driving member increases to or 'above a'value at which the valve is in its fully closed'position, then the speed of the driven member is again proportional to the speed ofthe driving member. It should be apparent to those skilled in the art that the range in speed of the driving member in which the control is effective to maintain the speed of Ithe driving member substantially constantas well as the predetermined speed at 'which the driven member is to be rotated may be varied to meet the requirements of different installations by suitably designing the component parts of the system.

In so far as principles of operation and construction are concerned, the modification of the invention illustrated in Figs. 6 and 9 is substantially the same as that of the previously described modification. In distinction therefrom, it may be stated 'briefly that the centrifugal governing and iiuid pressure generating means are driven directly by the driven member, instead of by the belt, and the ydiameter of the variable diameter driving pulley is controlled by varying the position of the axis of rotation of the latter with respect to the axis of rotation of the driven pulley. The driving member which may be either a driven shaft or a car wheel axle, as in the previously described modification, is indicated by the'refer ence numeral 19, Keyed to this shaft is a driving gear 1'! meshing with a gear 'l2 keyed to a jack shaft 73. The jack shaft is maintained parallel and equidistant to the drive shaft itl by a pair of parallel linkage members I4.

The driving pulley l5, similar vto the previously described driving pulley, is connected by a standard'V-belt to a driven shaft T! coupled directly to a constant speed compressor 18 'or other piece of equipment. The shaft 71 may be rotatably supported in a plurality of bearing brackets 1S (only one of Which is shown in Fig. 6). .On it is mounted the xed diameter driven pulley 8B.

In the present modification, the fluid pressure generating means is of the type that operates satisfactorily irrespective of the direction of rotation of its actuating shaft. A generating means of this 'type is one comprising a reciprocating piston. In the instant illustration an eccentric 8l., mounted for rotation .with the driven shaft This connected by a pitman 82 and a pivotal connection 83 to the plunger 84 of the oil pump. rihe plunger is slidably mounted within a pump cylinder 85 provided with an inlet check valve 86 controlling the supply of oil flowing to the pump through supply line 81 and oil reservoir 98. The reservoir is closed by a combined cap and breather 88.

The oil reservoir is connected to the outlet port of the oil pump by a bypass conduit 90 having interposed therein a valve 9| biased by spring means 9| to its open position and actuated by centrifugal means rotated by the driven member. The valve is provided with an extension connected to an actuating lever 92 rotatably mounted upon a rock shaft 93. The rock shaft is rotated by a yoke 94 in turn adapted to be moved longitudinally of the driven shaft 11 by a sliding collar 11. The sliding collar is moved along the shaft by a suitable centrifugal mechanism comprising the governor balls 95.

The outlet port of the oil pump is connected through a conduit 96 to a control cylinder 91 pivotally mounted upon a suitable supporting structure 98. Within the cylinder is mounted a piston 99 connected by a piston rod |00 to a yoke |02 pivotally connected to the jack shaft 13. Leakage of oil along the piston rod is prevented by a stuffing block |0|.

In this modification the compression springs associated with the driven pulley 80 normally bias the pulley halves together so os to maintain the pulley in its maximum diameter position. The spring bias moves the jack shaft 13 clockwise about the driving shaft and the piston 99 toward the right end of the cylinder, as viewed in Fig. 6. The bypass valve 9| is normally in its open position although in Fig. 6 it has been illustrated more nearly in its closed position, which is the position it occupies when the jack shaft has been moved to an intermediate position along its path of movement. The dotted lines in Fig. 6 indicate the eXtreme positions of the pulley.

The operation of the present modification is substantially the same as that of the one previously described except that the system is operative irrespective of the direction of rotation and that the effective diameter of the driving pulley is controlled by varying the distance between the axes of rotation of the pulleys and 80,

t should be apparent to those skilled in the art that the advantages of this modification may be utilized in connection with the previously described modification.

In-the modification of the invention illustrated Figs. '1 and 8 an increased range of speed ofthe driving member is compensated for by making both the driving and driven pulleys of the variable diameter type. These are so arranged that the driven member can be driven at a speed many times that of the driving member. One of the two pulleys is of the type comprising two pulley halves biased towardr each other by springs, and the other is so constructed that the position of the two pulley halves is determined by the belt tension and the force applied to the halves by centrifugally controlled pressure generating means. Y

Referring now specifically to Figs. '1 and 8, it may be seen Vthat the driving shaft, which may be rotated by a suitable prime mover, isv indicated by reference numeral |03. On it is mounted a variable diameter pulley |04 of the type having its opposed halves biased for movement toward each other by a pair of compression springs just as the pulley of the first described embodiment. A V-belt |05 interconnects the driving pulley and a driven pulley |01 comprising a pair of pulley halves |08 and |09 that are relatively movable with respect to each other in a manner to be described shortly. The driven pulley is mounted a driven shaft |66 adapted to be coupled to constant speed equipment by a coupling member |0.

The driven pulley and the speed-ratio varying means associated therewith are mounted for rotation in a pair of spaced apart bearing brackets The driven shaft |06 is provided with an annular flange ||2 so as to receive one end of an intermediate tubular shaft section ||3 to the other end of which is secured a tubular shaft extension |06'. The driven shaft proper |06, intermediate section ||3, and the extension |06 are made to rotate as a single unit by interconnecting the shaft and intermediate section by a key ||4 and the intermediate section and the-extension by'screws |25 extending through the in termediate section into a block |24 formed integrally with the extension.

The two halves |08 and |09 of the driven pulley are slidably splined to the exterior of intermediate section ||3. In Ythe interior of the section is slidably mounted a cylinder H5 connected by radially disposed pins I5, a collar |1 surrounding shaft section H3, and axially disposed rods Il to pulley half |09 in such manner that the two move as a unit. Slidably mounted within cylinder ||5 and movable as a unit with l-the other pulley half |08 is a piston ||9 suitably secured to a piston rod |20. Within the piston is a duct |20 providing a fluid passage `from the interior of the cylinder to the outlet of'the fluid pressure generating means to be described hereinafter.

The connection of the piston i9 to pulley ha |08 is madethrough concentric slidable collars |2| and |22 located Within and without the intermediate shaft section 3 and axially disposed rods |23, passing through suitable apertures in pulley half |09.

The pressure generating means comprises an eccentric |26 rotatable with the driven shaft and connected by a pitman |21 to a reciprocable plunger |28. The plunger is reciprocated within a cylinder |29 provided with intake and discharge check valves |30 and |3|, respectively. The intake of the pump is connected by a conduit |32 to the fluid reservoir |33 closed by a cap |34.

Thek iiuid pressure tending to force the pulley halves |08 and |09 toward each other is controlled by a normally open valve |35 located within a valve housing |35. The valve controls, as in the previously described modifications, the flow of fluid through a bypass conduit |31. The outlet side'of the pump is connected to the cylinder ||5 through the previously mentioned hollow in it .-a

To permit ready movement of the piston The principles of operation of this device are similar to those of the previouslydescribed embodiments of the invention. When the system is at rest, the valve |35 is in its fully open position.

As a result, the pressure tending toforce apart'` cylinder andpiston. |9'is.. at aminimum so that the pulley halves are forced apart to their minimum diameter position by thev tensionexerted on the belt by the compression springs.

biasing the halves of the driving pulley to a maximum diameter position. Then when the driving shaft is rotated, the driven shaft is rotated at a speed'ratio greater than one because.

the maximum diameter of the driving pulley is greater than the minimum diameter of the driven pulley. As the speed of the driving member increases, the driven member is driven at a speed proportional to the. speed of the driving member until the driven shaft exceeds its normal speed. Thereafter, as the speed of the driving member continues to increase, the centrifugal controleffects gradual closure of the bypass valve |35, gradually to apply an increasingV pressure tending-to force together the pulley halves |08 and |09; This force gradually overcomes the force of the belt tending to force the halves apart,

anda-sa result, the diameter of Ythe driven pulleyV member increases above fa point 'at which the valve `isfully closed then, asin the previously described modifications, the speed of the driven member again becomes proportional tothe speed of the driving member.

Upon ya decrease in speed, just Vtheopposite re'- sul-ts are obtained. Therefore, the-'driven mem-` ber is rotated at a substantially constant speed, irrespective of the variationsin speediof the-driving member.

It is contemplated thatnumerous changes may* be madev in the specic embodiments described` above .without departing `from the spiritof the present invention. For-instance, it' should, be

understood that the physical constants ofthe various elements may be Lmodified to'meetthe varyingV requirementsl ofn diverse applications.

Likewise, it may be desirable in some instancesr` to connect the centrifugal controlto the driven member through suitable gears vor tooperate the pressure generating means through gears instead of by an eccentric mounted upon the driven shaft. Furthermore, it is possible to reverse the direction of operation of the valve and its actu-l ating means, so that the valve is normally closed instead of open. Othe1` ,changes may well occur to those skilled in the v-art and, therefore, thev invention is not to be restricted except by the appended claims.

What I claim as new and desire to secure by- Letters Patent is:

1. In combination, a .varying speed driving member, a member to be driven at a substantially constant speed, variable speed-ratio means interconnecting. said..` members. and.` resilientlyV biased to a high speed-ratio position, and means adapted automatically` .to control the: speed-ratio of said last mentioned means whereby. said driven member is driven atsubstantially a constant speed irrespective of variations inthe speed' of the driving member, said last mentioned means including' a pump operated by power derived from the vdriving member `and operable only when the driving member is rotated, fluid pressure operated means connected to the outlet of the pump and actuable solelyv byfpressu-re developed by said pump and operating against the biasling the pressure applied to said pressureoperated means.

2. In a power transmission system, thecombination including, a varying speed driving member, a member to be driven at'a substantially constant speed, variable speed-ratio means in# terconnectingv said members, and means adapted automatically to control the'speed ratioof said last mentioned Vmeans whereby said driven' member isdriven at a substantially constant 25fspeed irrespective of 'variations in the speed of the driving member; said last mentioned means includ-ing fluid pressurefgenerating' means opferated by power derivedfrom the drivingmemsber, pressure operated means controllingsaid variable speed-ratio means, `variable position 'valve means interposed `between said pressure generating and pressureoperated means for varying. the pressure appliedlto said pressure operated means,`

zand' centrifugally operated meansfoperatingat aiv 'speed proportional to that of the driven member" for controllingthe position of said valve.

3. rIn a power transmission system, thecombination including, a Varying speed driving member, a member'to be :driven at a"substantial1yr 'constant speed, a Variable diameter pulleyof the typeincluding a pair of pulleyhalvesresiliently biased vtoward a= maximum diameter position mounted on oneof said members, means inter-I connecting said members through said pulley. for

the `transmission of power from one tothe other,

fluid pressure generatingmeans,` means for operating said pressuregenerating means bypower? derived from-thefdrving` member,` pressurejoperatedfmeans adapted to varyJthe-dstancebetween the pulley halves against the biasing forcefor varying the speedratio'between said driving and driven members, valve means inter-posed between said pressure generating and pressure operated means for varying .thepressure applied to the latter means, andcentrifugally operatedmeans operating at a speed proportional vto that of the drivenfmember adapted to controlsaid valve means for maintainingthe speed ofthe driven member substantially constant.

4. In a rpower transmission system, the combination including,y a varying speed driving member, a member to be driven at a substantially constant speed, a'variable diameterpulley of the type including a pair ofpulley halves resilientlyy biased toward a maximum diameter position mounted on one of said members, abelt inter-- ing Vforce forvarying. the diameterl of 'saidpulley and thereby the speed ratio betweenhe'driving and driven members, a iiuid conduit leading from the outlet port of said pump to the cylinder, a iluid reservoir, a fluid conduit connecting said reservoir to the suction port of said pump, a bypass conduit connecting the outlet port of said pump to the fluid reservoir, a valve means controlling the iiow of fluid through said bypass conduit, and centrifugally operated means operating at a speed proportional to that of the driven member adapted to control said valve means whereby the pressure applied to said piston is varied to maintain the speed of the driven member substantially constant irrespective of the variations in the speed of the driving member.

5. In combination, a driving member, a driven member, variable speed-ratio means interconnecting said members, and means including iiuid pressure generating means and centrifugally controlled valve means actuated by and acting upon said last mentioned means for controlling the speed ratio.

6. In combination, a driving member, a driven member, a flexible driving connection interconnecting said members for transmitting power from one of said members to the other, means responsive to the pressure applied to said connection for varying the speed-ratio of said members, and means for varying the pressure applied to said connection for varying the speed ratio to maintain the speed of the driven member substantially constant, said last mentioned means including iiuid pressure generating means driven by said connection, a pressure applying member operated thereby, and centrifugally controlled valve means driven by said connection for regulating the pressure applied to said connection.

7. In combination, a driving member, a driven member, variable speed-ratio means interconnecting said members, and means including fluid pressure generating means and centrifugally controlled valve means comprising a unitary structure and actuated by and acting upon said speed-ratio means for controlling the speed ratio.

8. In combination, a varying speed driving member, a member to be driven at a substantially constant speed, variable speed-ratio means including a variable diameter pulleyl and a belt interconnecting said members, and means adapted to control the force applied to said belt for varying the speed-ratio and driving said driven member at substantially a constant speed irrespective of variations in the speed of the driving member, said last mentioned means including fluid pressure generating means driven by the belt, pressure operated means for applying a variable force to the belt at a point between said members, and means in contact with and driven by the belt at a speed proportional to the speed of the driven member for controlling the pressure applied to said pressure operated means.

9. In a power transmission system, the combination including, a varying speed driving member, such member having secured thereon a pulley including a pair of pulley halves resiliently biased toward each other, a member to be driven -at a substantially constant speed, a belt interconnecting said members, fluid pressure generating means operated by power derived from the belt, pressure operated means adapted to vary the pressure applied to said belt and thereby to vary the distance between the pulley halves for varying the speed ratio between said driving and driven members, valve means interposed between said pressure generating and pressure operated means for varying the pressure applied to the latter, and centrifugally operated means driven by the belt at a speed proportional to that of the driven member and adapted to control said valve means for maintaining the speed of the driven member substantially constant.A

10. In a power transmission system, the combination including, a varying speed driving member, a variable diameter pulley of the type including a pair of pulley halves resiliently biased toward a maximum diameter position mounted on said member, a member to be driven at a substantially constant speed, a belt interconnecting said members for the transmission of power from one to the other, fluid pressure generating means comprising a pump having suction and outlet ports operated by the belt, means including a cylinder and associated piston acting against the force biasing said pulley halves together for varying the diameter of said pulley andthereby the speed ratio between the driving and driven members, a uid conduit leading from the outlet port of said pump to the cylinder, a iiuid reservoir, a fluid conduit connecting said reservoir to the inlet port of said pump, a bypass conduit connecting the outlet port of said pump to the iiuid reservoir, valve means controlling the flow of fluid through said bypass conduit, means biasing said valve toward its open position, centrifugally operated means rotating at a speed proportional to that of the driven member and driven by the belt adapted to-open said valve biasing means in response to an increase in speed above a predetermined valve ing with the driven member for controlling the whereby the pressure applied to said piston is varied to maintain the speed of the driven member substantially constant irrespective of the variation in the speed of the driving member, and a unitary support independent of the driving and driven members and interconnecting belt for the elements of the speed-ratio varying means.

11. In combination, a varying speed driving member, a member to be driven at substantially a constant speed, variable speed ratio means including a variable diameter pulley and a belt interconnecting said members, and means adapted to vary the position of the driving member with respect to said driven member for varying the diameter of said pulley and driving said driven member at a substantially constant speed irrespective of variations in the Speed of the driving member, the last mentioned means including iiuid pressure generating means driven through the intermediary of the driven member,

pressure operated means for varying the position of the driving member with respect to the position of the driven member, and means rotatpressure applied to said pressure operated means.

12. In a power transmission system, the combination including, a varying speed driving member, a pulley of the type comprising a .pair

of pulley halves resiliently biased towardv each Y other secured on said member, a 'member to be driven at a substantially constant speed, a belt member for operation thereby, pressure operated means adapted to vary the distance between lthe driving and driven members thereby to vary the distance between the pulley halves for varying the speed ratio between said driving and driven' members, valve means interposed between said pressure generating and pressure operated means for varying the pressure applied to the latter means, and centrifugally operated means driven by said driven member adapted to control said valve for maintaining the speed of the driven member substantially constant.

13. ln a power transmission system, the combination including a varying speed driving member, a driving pulley of the type comprising a pair of pulley halves resiliently biased toward each other mounted on said member, a member to be driven at a substantially constant speed, a belt interconnecting said members for the `transmission of power from one to the other, a fluid pressure generating pump of the reciprocating type having suction and outlet ports operated by power derived from the driving member through the intermediary of the belt and driven member, means including a cylinder and an associated piston for moving the axis of rotation of the driving member with respect to the axis of rotation of the driven member thereby to control the distance between the pulley halves and the speed ratio between the driving and driven members, a iiuid conduit leading from the outlet port of said pump to the cylinder, a iluid reservoir, a fluid conduit connecting said reservoir to `the inlet port of said pump, a bypass conduit connecting the outlet port of said pump to the fluid reservoir, valve means controlling the flow of fluid through said bypass conduit, and centrifugally operated means driven directly by the driven member for controlling the position of said valve means, said centriiugally operated means and valve means being so constructed and arranged that when the driving member is at rest the valve is open and as the speed of the driving member and driven member increases above a predetermined value the centriiugally operated means is effective gradually to close the valve to increase the pressure applied to said piston and move the driving pulley with respect to the driven member thereby to maintain substantially constant the speed of the driven member irrespective of variations in the speed of the driving member.

14. In combination, a varying speed driving member, a driving pulley of the type including a pair of pulley halves biased toward each other mounted on said member, a driven member adapted to be driven at a substantially constant speed, a driven pulley comprising a pair of pulley halves movable axially with respect to each other mounted on said driven member, a belt interconnecting said pulleys, and means adapted to control the position oi the two last mentioned pulley halves with respect to each other for varying the speed ratio and for driving said driven member at a substantially constant speed irrespective of variation in the speed of the driving member, said last mentioned means including nuid pressure generating means driven by said driven member, means operable by pressure from said pressure generating means for varying the position of the two last mentioned pulley halves with respect to each other, and means driven by the driven shaft at a speed proportional thereto for controlling the pressure applied to said pressure operated means.

l5. In a power transmission system, the combination including a varying speed driving member, a pulley of the type having a pair of pulley halves resiliently biased toward each other secured to said driving member, a member to be driven at a substantially ccnstantjspeed, a variable diameter fpulleyof the Itype having a pair of pulley halves relatively movable axially with respect to each other secured to said driven member, a belt interconnecting said pulleys for the transmission of power from one member to the other, iiuid pressure generating means operated by the driven member, pressure operated means adapted to vary the positions of the two last mentioned pulley halves with respectvto each other for varying the speed ratio between the driving and driven members, valve means interposed between said pressure generating and pressure operated means for varying the pressure applied to the latter, and centrifugally operated means driven by the driven member adaptedto control said valve means for maintaining. the speed of the driven member substantially constant.

16. In a power transmission system, ythe combination including a varying speed driving member, apair of-pulley halves resiliently biased toward `eachother secured on said member, a member adapted to be driven at a substantially constant speed, a pulley of the type having a pair of pulley halvesv relatively movable axially with respect to each other mounted on said driven member, a belt interconnecting said pulleys for the transmission of power from one member to the other, a fluid pressure generating pump of the re ciprocating type having suction and outlet ports operated by power derived from the driving member through the intermediary of the belt and pulleys, means including a relatively movable piston and cylinder connected to said two last mentioned pulley halves and operable to vary thedistance between said halves for controlling the speed ratio between the driving and driven members, a iiuid conduit leading from the outlet port of said pump to the cylinder, a fluid reservoir, a fluid conduit connecting said reservoir to the suction port of said pump, a bypass conduit connecting the outlet port of said pump to said fluid reservoir, valve means controlling the flow of fluid to said bypass conduit, and centrifugally operated means driven directly by the driven member for controlling said valve means whereby the pressure applied to said piston is varied to maintain the speed of the driven member substantially constant irrespective of the variations in the speed of the driving member above a predetermined valve, said centrifugally operated means and valve means being so constructed and arranged that the bypass conduit is open when the driving member is at rest and the conduit is gradually closed as the speed of the driven member increases above said predetermined value.

17. In combination, a varying speed driving member, a driving pulley of the type including a pair of pulley halves biased toward each other mounted on said member, a driven member adapted to be driven at a substantially constant speed, a driven pulley comprising a pair of movable pulley halves mounted on said driven member, a belt interconnecting said pulleys, and means adapted to control the position of the two last mentioned pulley halves with respect to each other for varying the speed ratio and for driving said driven member at a substantially constant speed, said last mentioned means including fluid pressure generating means driven by said driven member, a movable cylinder connected to one and a movable piston connected to the other of said two last mentioned pulley halves, said cylinder and piston defining a chamber, means connecting said chamber to said iluid pressure generating means, and means driven at a speed proportional to the driven shaft controlling the pressure applied to the chamber.

18. In combination, a varying speed driving member, a driving pulley of the type including a pair of pulley halves biased toward each other mounted on said member, a driven member adapted to be driven at a substantially constant speed and comprising a tubular portion, a driven pulley comprising a pair of movable pulley halves mounted on the tubular portion of said driven member, a belt interconnecting said pulleys, and means adapted to control the position of the two last mentioned pulley halves with respect to each other for varying the speed ratio and for driving said driven member at a substantially constant speed, said last mentioned means including uid pressure generating means driven by said driven member, a movable cylinder connected -to one and a movable piston connected to the other of said two last mentioned pulley halves, said cylinder and piston being positioned within the tubular portion of said driven member and defining a pressure chamber, a conduit movable with said piston connecting said chamber to said pressure generating means, and means driven at a speed proportional to the driven shaft controlling the pressure applied to said pressure chamber through said conduit.

19. In a power transmission system, the combination including, a power transmitting member comprising a tubular portion, a pair of movable pulley halves mounted on said tubular portion, and means for controlling the relative positions of said pulley halves, said last mentioned means comprising a cylinder movably mounted within said tubular portion and connected to one of said pulley halves, a piston movably mounted within said tubular portion and connected to the other of said pulley halves, said piston being cooperatively associated with said cylinder to define a pressure chamber, and means for applying pressure between said cylinder and piston.

20. In a power transmission system the combination including, a varying speed driving member, a .pair of pulley halves resiliently biased toward each other secured to said member, a member adapted to be driven at a substantially constant speed and comprising a tubular section mounted for rotation on a pair of spaced-apart brackets, a pair of movable pulley halves mounted on said tubular portion, a belt interconnecting said pulleys for the transmission of power from one member to the other, a reversible fluid pressure generating pump operated by power derived from the driving member through the intermediary of the belt and pulleys, means including a movable piston and movable cylinder each connected to one of said two last mentioned pulley halves for controlling the speed ratio between the driving and driven members, a fluid conduit leading from the discharge side of said pump to the chamber dened by said piston and cylinder, said conduit extending through one of said spaced-apart brackets, valve means associated with said conduit for controlling the pressure in the chamber between said piston and cylinder, and centrifugally operated means driven at a speed proportional -to that of the driven member-for controlling said valve.

AUGUSTUS C. DURDIN, JR.

CERTIFCATE OF CORRECTION. Patent No. 2,508,868. January 19, l9h5.

' AUGUSTUS C. DURDN, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 6, geeond column, line 56, claim lO, and page?, second column, line 5l, claim 16, fOr Valve read --value--g and that the said Letters Patent shouldbe read ction therein that the same may conform tothe record ofthe with this corre ease in the Patent Office.

signed and Sealed this 50th day of March, A. D. 19M.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

